The main executable stores all of the game sprites excluding those used by alien ships and buildings. In the WHDLoad version, the sprites are visible from offset 256252 in the main game executable, immediatly following a large area of zero'd data. These sprites are most easily viewed with a width of 32 bits. The sprites do appear to include some structures used by aliens, notably the animated building used by the tylaran empire, viewable here: http://imgur.com/IT7zkXJ

The sprite data appears to end at around offset 362056 with all of the menu interface buttons. The WHDLoad game executable is roughly contains roughly 103.3kb of raw image data or 22.5% of the file.

checksum

Appears to be a program to check or generate checksums. The symbol table is intact. It has one section, according to an IRA disassembly: